Secondhand nicotine does you no harm. The reason cigarettes are so bad for you is that you’re smoking tar. That’s what makes the walls of a smokers home yellow, and what gives them cancer.
Nicotine is addictive, but largely harmless at the levels in cigarettes and vapes for the primary smoker. A secondhand smoker will be getting almost nothing. The problem with vapes is, I suspect, the flavourings. I’m aware of mounting evidence that they’re not harmless, but I think that’s only to primary vapers, not secondary.
Not ban. Regulate, like food. Have standards and enforce them.